Numerous procedures exist for inserting medical devices into a patient's body percutaneously, i.e. through the skin. Various abdominal surgical procedures utilize laparoscopic techniques which allow the percutaneous penetration of surgical tools without making a large skin incision. Other techniques utilize percutaneous endoscopic gastrostomy (PEG) to place gastrostomy tubes.
Laparoscopic techniques for establishing a surgical port typically involve inserting an insufflating needle within a sheath and pushing the needle/sheath assembly through the skin and into the abdomen. The needle is used to inflate the abdominal cavity with an insufflating gas. Once the abdomen is insufflated, the needle is removed from inside the sheath and a trocar is inserted into the central lumen of a fixed diameter access port. The trocar and the access port are then inserted into the initial penetration site, through the sheath, and forced into the abdomen. The trocar and the sheath are then removed, leaving the access port in place for use during surgery.
The trocars used in laparoscopy usually have a knife-like tapered distal end with two sharp leading edges extending from the main trocar body to the distal end. The sharp leading edges form a wedge which is as wide as the trocar diameter at the point of attachment to the main body and tapers distally ending in a sharp distal tip. This large cutting edge slices through tissue during insertion, causing trauma to the body tissue and increasing healing time. Additionally, when using such trocars, surgeons risk damaging the target organ or other organs if they fail to stop the distal insertion force of the trocar in a timely fashion or if they fail to properly control the forces associated with such penetration. Some laparascopic trocars have been equipped with distally-biased sheaths which automatically cover the leading edge upon penetration of the target organ wall (e.g., U.S. Pat. No. 5,346,459, the contents of which are incorporated herein by reference.) Other trocars have an electrically charged tip for cutting tissue. Once the tip has penetrated the target organ, the electrical supply is cut off. (See U.S. Pat. No. 5,344,420.) Although these improved trocars prevent damaging organs subsequent to target organ penetration, they do little to lessen the trauma to abdominal tissue during penetration.
Three main percutaneous endoscopic gastrostomy techniques are used to place gastrostomy tubes within the stomach: Sacks-Vine, Ponsky, and Russell.
The Sacks-Vine technique involves inserting an endoscope into the patient's mouth, down the esophagus, and into the stomach; insufflating the stomach, and then using endoscopic illumination to locate the optimal percutaneous penetration point. A special needle, having a penetrating portion and a surrounding cannula, is then inserted through the abdominal wall and into the stomach so that it penetrates at the located point. The needle is removed, leaving the cannula in place, and a guidewire is inserted through the cannula. An endoscope snare is then used to grab the guidewire from inside the stomach and pull it up the esophagus and out the mouth. Next, a gastrostomy tube, with a tapered catheter attached to its distal end, is inserted over the guidewire down into the stomach. The guidewire is then used to pull the catheter through the percutaneous penetration. Finally, the catheter is then cut from the gastrostomy tube, leaving the tube in place within the stomach.
With the Ponsky technique, a wire with a looped end is attached to a needle, inserted through the abdominal wall and into the stomach. An endoscope snare is used to hook the loop and pull the wire up the esophagus and out the mouth. A second wire with fixed loop is attached to the distal end of a tapered catheter. The proximal end of the catheter is then attached to the distal end of a gastrostomy tube. Next, the loop of the percutaneously inserted wire is then hooked to the wire attached to the tapered catheter. The percutaneously inserted wire is then pulled from outside the abdominal wall, drawing the tube down the esophagus, into the stomach, and out the insertion site. The catheter is then cut from the gastrostomy tube, leaving the tube in place within the stomach.
With the Russell technique, a needle is percutaneously inserted into the stomach, and a guidewire is inserted into the stomach through the needle. The needle is removed, leaving the guidewire in place, and a series of tapered dilators with increasingly larger diameters are inserted one at a time over the guidewire and into the stomach. Each dilator insertion increases the size of the penetration. The final dilator may have a removable sheath which is inserted into the stomach along with the dilator. The final dilator is then removed, leaving the sheath in place. The gastrostomy tube can then be inserted through the sheath and into the stomach. The sheath is then removed from around the tube.
Practitioners have encountered numerous problems when using these prior art PEG techniques. The Sacks-Vine is a complicated and cumbersome technique which often requires more than one person to perform. In addition, dragging the gastrostomy tube through the esophagus often leads to extreme patient discomfort, trauma to esophagus, internal bleeding, and sometimes gastro-esophageal reflux condition. Furthermore, both the Sacks-Vine and Ponsky techniques entail dragging tube and wire through mouth, esophagus, stomach, and abdominal wall which increases the risk of abdominal infection.
In the Russell procedure, the dilator must closely follow the line of the guidewire, so as not to buckle the wire into the peritoneal cavity. If the wire were to buckle, the practitioner might force the dilator into contact with the stomach at a site other than the optimal penetration site, damaging the stomach or other organs. This need to prevent wire buckling during insertion slows down the placement procedure.
In addition, the Russell technique involves forcibly inserting a dilator into the stomach wall through a penetration smaller than the dilator diameter. The stomach wall is quite thick and will indent, or tent, when pushed distally by the dilator. Any attempt to dilate a tented stomach wall by continuing the distal force increases the risk of damaging the stomach or surrounding organs. To aid in dilation when using the Russell technique, practitioners often employ a twisting motion during insertion. This twisting motion increases trauma to tissues of the abdominal and stomach walls.
The tendency of the stomach wall to tent during dilation makes percutaneous placement of gastrostomy tubes difficult. In a tented state, the anterior stomach wall is pushed closer to the posterior stomach wall. Tenting increases the risk that the practitioner will pierce both the anterior and posterior walls during dilation.
Tenting can lead to improper placement of the tube as well. The medical practitioner performing the procedure must be careful to fully penetrate the stomach wall during dilation. If the tube placement is attempted without complete dilator penetration, the practitioner may inadvertently place the tube within the peritoneal cavity, instead of the target organ. Such improper placement can have fatal consequences. The peritoneal cavity, located between the peritoneum and the stomach, is sterile and susceptible to infection. Because peritoneal infection often goes undetected until it has become severe and internal bleeding occurs, improper tube placement can have fatal consequences.
Numerous devices for radially expanding a penetration can be found in the prior art. Examples of the various prior art devices are found in U.S. Pat. Nos. 5,183,464, 5,431,676, 5,573,517, the contents of which are hereby incorporated by reference.
Additional examples of apparatus and methods for percutaneously placing access tubes can be found in U.S. Pat. Nos. 5,454,790, 5,577,993, and 5,312,360, the contents of which are also hereby incorporated by reference.
There is a need for an apparatus which prevents the target organ wall (e.g. the wall of the stomach) from tenting during percutaneous placement of gastro-intestinal tubes. There is also a need for an apparatus that does not prolong patient recovery by causing tissue trauma during such placement, and a method for percutaneously placing gastrostomy tubes which prevents organ tenting, minimizes tissue trauma.